(INDIANAPOLIS)(WXIN) - Around 5:30 p.m. Wednesday, the driver of an IndyGo bus was picking up riders when she noticed a grey Buick at the Marathon on North Mickley Avenue begin to roll backwards with no one inside or so she thought.

The grey Buick continued rolling in reverse down a hill into oncoming traffic. It then hit the drivers side of the IndyGo bus. When the driver of that bus got out to look inside the car, she got the surprise of her life.

Sitting in the driver's seat was none other than 3-year-old DeAdrian and in the back, without a car seat, was his 2-year-old cousin Jakina.

Moments before the crash, DeAdrian's mom, 23-year-old Saprina Ashburn, had gone into the Marathon to buy cigarettes. She had left her keys in the ignition and the car unlocked.

That's when, according to the police report, DeAndrian "climbed over the back seat into the driver's seat" where he "started the ignition and somehow got the vehicle's gear into reverse. "

Police arrested Ashburn for cruelty neglect of a dependent and the kids were turned over to her boyfriend.

Police said they aren't surprised that DeAdrian knew what he was doing.

"They watch what you do. They watch how things are operated and they try to mimic you or they try to mimic an adult or things that they like. So it's not surprising that he knew how the car started or how to put the car in gear," said Anthony Schneider, Public Information Officer for IMPD.

Police advice whatever you do, don't leave children with any opportunities.

"If you're going inside, take the kids inside. Nowadays anything can happen in an instant," said Schneider.